NEW PARTS FOR VC-2 BOILER CHECK VALVES

The Orange Empire Railroad Museum‘s operating steam locomotive is the Ventura County Railroad No.2, the VC-2 as we know it. Like all steam locomotives, the VC-2 has its balky moments when steamed-up. The boiler water injectors, vital to safe operation, were becoming hard to start. They never failed to start, but the starting difficulty was a pain-the-ass thing for the crew. An inspection revealed the boiler water check valves were at fault due to excessive wear. The inspection also revealed cracks in the check valve cover nuts. New check valve parts were needed. The OERM Machine Shop got the job after a suitable amount of begging by the Steam Crew was noted and approved by the Machine Shop personel. This the story of the making of the required parts.

An agreement was reached that established the material to be used, dimensions of the parts, general design, and the date of completion. All this is made necessary by the complete lack of part drawings, as is usual in the repair and maintenance of antique railroad machinery. The initial machining of the parts consisted of routine lathe work and was accomplished without any difficulty. A thread plug gage was made to ensure the nut would fit the check valve housing after the nut was threaded on the lathe. The next machining operation was the milling of the fins of the check valves. This operation was a complicated one as the valve fins were slightly angled from the center-line of the valve to cause the moving water to impart a rotation to the valve so as to evenly distribute valve seat wear. The shop is blessed with an early version of a CNC vertical milling machine. However, it is so “early” it requires the use of punched paper tape to input the CNC program data. An ancient laptop computer is used to emulate punched paper tape, of which we have none. This machine gets the job done so we are fortunate to have it. The fin geometry was analyzed and a moderately complex G-code control program was written to achieve the required fin shape. The program was de-bugged while machining a wooden test piece. The subsequent machining of the valve fins was done without major incident.

The parts were finished in the lathe and delivered to the Steam Crew and were installed in the check valve assemblies without delay. The following locomotive steam-up revealed the injector start problem was gone. The injectors remain problem free to this day.

Photographs of the making of the check valves are presented in the gallery below. Click on any photograph to enlarge the view.

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